On 12/17/2008 09:48, wb8icn posted:
Did some benchmarking of the rf amp that Diz has using the 2N5109.

I can see me using this one alot for projects! To see my test results,
go to http://www.qsl.net/wb8icn/UWA%20-%202N5109%20-%20Characteristics.html

72's/73's....Mikey, WB8ICN
www.qsl.net/wb8icn
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On 12/17/2008 16:39, W8DIZ posted:
[wb8icn wrote:] "Did some benchmarking of the rf amp that Diz has using the 2N5109.
I can see me using this one alot for projects! To see my test results,
go to http://www.qsl.net/wb8icn/UWA%20-%202N5109%20-%20Characteristics.html
72's/73's....Mikey, WB8ICN
www.qsl.net/wb8icn
"


How come everybody has better test equipment than me ? :(
-Diz
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On 12/17/2008 20:14, kc0wox posted:
I liked his setup also. It was a lot like mine.
Leonard
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On 09/09/2011 17:26, Vern posted:
Kinda old stuff with a 2008 date but what the hey....

Run this amp with -19dbm in and get 0dbm out. Noticed the transistor is warm. Believe I could pinch it with with my fingers without burning my fingers. Is it wise to put a heat sink on it?

Also, was it designed to run indefinitely/continuously? That's what I want to do with it.

I suspect the 'chief in charge' will read this so while I have your attention, a question. Are there spare transistors available for the 5watt HF CW amplifier - 2SC5739's ??

TU for reading.

Vern W9HLY
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On 09/09/2011 20:44, W8DIZ posted:
[Vern wrote:] "Kinda old stuff with a 2008 date but what the hey....

Run this amp with -19dbm in and get 0dbm out. Noticed the transistor is warm. Believe I could pinch it with with my fingers without burning my fingers. Is it wise to put a heat sink on it?

Also, was it designed to run indefinitely/continuously? That's what I want to do with it.

I suspect the 'chief in charge' will read this so while I have your attention, a question. Are there spare transistors available for the 5watt HF CW amplifier - 2SC5739's ??

TU for reading.

Vern W9HLY
"


Hi Vern,
The RF Amp is designed to run hot, but not too hot that it will burn you.
It can run 100 pct duty cycle.
Only have about 8 pieces of 2SC5739 for emergency repairs.
-Diz
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On 09/09/2011 21:15, ak2b posted:
I picked up some 2SC5739'S from Talon Electronics last week but it seems he is running out of them also. He had only three left as of a few minutes ago.
W7ZOI uses the same transistor in "An Updated Universal QRP Transmitter" and has substituted a BD139 with good results. Be careful though, the pinout is just the opposite.

Tom, ak2b
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On 09/20/2011 09:51, n1kk posted:
what is the max input voltage this circuit will handle for drive?
I am looking for an amp that can give me 5-6 volts of RF (15-20v pk-pk)
That's around a 30dBM output.

Ken
N1KK
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On 02/17/2013 23:49, KC7NOA posted:
WB8ICN site hits with a complaining virus scanner of having a trojan ...

Soooo ... what is the max drive?? 10dbm??
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On 02/28/2013 13:09, KC7NOA posted:
another question ...

why use FT-61 material for T1 & T2 .... or is that BN-61-202 ?
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On 03/03/2013 13:21, KC7NOA posted:
thought i asked this question before .. i cant find the answer ...
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On 03/04/2013 06:23, W8DIZ posted:
[KC7NOA wrote:] "another question ...why use FT-61 material for T1 & T2 .... or is that BN-61-202 ?"


The RF Amp does not use any -61 materials. Only toroid is a FT37-43...must be thinking of a different amp. - Diz
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On 03/04/2013 11:29, KC7NOA posted:
says right under the schematic .... thats where i got it from ..

http://kitsandparts.com/linearamp.php
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On 03/04/2013 11:38, KC7NOA posted:
[KC7NOA wrote:] "says right under the schematic .... thats where i got it from ..

http://kitsandparts.com/linearamp.php
"


So .. in the PDF T1 material is referred to as BN-61-202 .....

thats being used as a power transformer .... seen on the net it is spec'd as 0.5 to 10Mhz power transformer ---

im just fishing out why the 15M/10M drops off so bad .....
Its the main reason i never posted my mods for using RD06HHF1 and RD16HHF1's to this amp .....

Mike KC7NOA
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On 03/04/2013 15:41, W8DIZ posted:
Hi Mike,
This thread on the forum was about the RF Amp, not the linear amp...hence the confusion.
So what would you use if not a -61 for the transformers in the linear amp?
I used the -61 because it has lower losses than a -43 ferrite.
The upper freq limit is due to the 180 MHz FT of the finals.
73, Diz, W8DIZ
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On 03/14/2013 15:03, VE3SMF posted:
I just built one of the HF RF amplifier boards.
http://kitsandparts.com/rfamp1.1.php

I am using this to increase the signal on a N3ZI DDS2 VFO.
http://www.pongrance.com/ddfc-cc.html

Measurements are with a Fluke PM3092 oscilliscope. VFO signal is 7.055 Mhz

The output from the N3ZI DDS2 VFO is about 250 mV p-p (0.25 V p-p)

The output from the HF RF amplifier using 12 VDC when connected to the N3ZI DDS VFO with no attenuator restistors is 4.2 V p-p

The output from the HF RF amplifier using 12 VDC when connected to the N3ZI DDS VFO with attenuator restistors R5 = 150 ohm , R6 = 36 ohm and R7 = 150 ohm (6dB attenuation) is 2.1 V p-p

I need to reduce the output signal to around 1.15 V p-p (0.4 rms).

What values of resistor R5, R6 and R7 do I need in the attenuator?

My plans are to use the DDS2 VFO and HF RF amplifier to drive a Spilsbury SBX-11/SBX-11A transceiver. Any suggestions would be appreciated.

Cheers!
Stuart
VE3SMF
Ottawa, ON Canada.
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On 03/15/2013 07:55, W8DIZ posted:
You need to reduce the power by another (almost) 6 dB
or a total of about 11.5 dB
Looking up the numbers in the ARRL handbook (all data is in there)
and using standard valu resistor,
I recommend using 91 ohms of ALL the resistors
R5,6,and R7
73, Diz, W8DIZ
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On 02/02/2014 22:44, aa4ga posted:
I'm running this amp off 12 V and am using 1800 ohms for R4 as recommended. My output is around 7 V P-P...I'd like to drop it down a bit, to, say ~2.5 V P-P. I know I could add in an attenuator, but as an alternative, could I increase the value of R4 instead, and possibly draw less current and have the transistor run a bit cooler?

73 de Lee, AA4GA
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On 02/03/2014 07:27, W8DIZ posted:
[aa4ga wrote:] "I'm running this amp off 12 V and am using 1800 ohms for R4 as recommended. My output is around 7 V P-P...I'd like to drop it down a bit, to, say ~2.5 V P-P. I know I could add in an attenuator, but as an alternative, could I increase the value of R4 instead, and possibly draw less current and have the transistor run a bit cooler?
73 de Lee, AA4GA
"


Hello Lee,
I would increase the value of the emitter resistor until I got the desired RF output.
Change from 51 to maybe 75 or 82 or 100 ohms. - Diz
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On 02/03/2014 21:25, aa4ga posted:
Thanks, Diz - I'll probably give that a try.

73 de Lee
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On 06/05/2014 12:04, KE7FD posted:
(Newbie alert!)
I have two Rockmite radios: A 40M CW tranceiver and a PSK-40. The CW radio seems a bit weak so I'd like to jack it up to 5 watts; perhaps the same for the PSK-40. I'm looking at the 5 Watt CW RF Amplifier version 24-Nov-11, and was wondering if the Rockmites would have enough drive for this amp to work? Thoughts, comments anyone?

Glen
KE7FD
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